This is the ninth book plucked from my #40booksby40 list. I’ve read all Sarah Waters’ other novels, loved each of them in their different ways, but had put off The Little Stranger: ghost stories aren’t really my thing.

But I should have realised that, though this is an homage to the genre, Sarah Waters isn’t really telling a ghost story. Set in the aftermath of the Second World War this is a story about that very British obsession, class, and our inability to feel at ease with it.

It’s told by Dr Faraday, who – like his scientist namesake – is working-class ‘made good’, yet plagued by guilt at the sacrifices his parents made, feeling uncomfortably precarious as a middle-class professional, and remains brittly envious of the upper classes (represented by the Ayres family), no matter that they’re on their uppers.

As a child, he chiselled a decorative acorn from the moulding at the family’s Hundreds Hall, where his mother was in service. As an adult, he returns to ‘haunt’ it, literally if not figuratively.

Called in to treat a malingering servant, Betty, who complains of the house’s atmosphere (ironically she remains a something of ghost at the house for the rest of the book), Dr Faraday establishes himself as a trusted friend and confidante; as, simultaneously, the three surviving Ayres’s meet different, tragic, unexplained ends.

His vanilla demeanor and bland descriptions are at odds with the chaos that is unleashed by his presence in their lives. Is his the one voice of rational sanity in a world gone mad? Or is he an unreliable narrator of events he’s somehow set in train?

Waters is too canny an author to indulge the reader who wants to know for sure. Instead we are left frustratedly hanging with an unresolved and deliberately enigmatic ending, reading into it what we want, filling in the gaps according to our own assumptions. Just like people do in ghost stories, in fact.